The present invention relates generally to paper making machines and, more particularly, to a transfer arrangement for guiding a paper web from the press section of a paper machine to it's drying section.
The provision of a smoothing press between the drying and press sections of a paper making machine is known. A smoothing press generally includes two press rolls which form between them a smoothing nip, the web being passed to the smoothing nip from the press section either directly or guided by a guide roll or the like.
A smoothing press is, as a rule, used in a fine-paper making machine after the press section in order to smooth the faces of the paper web. A smoothing nip is formed between two smooth-faced press rolls. In most cases, no fabrics are passed through the smoothing nip so that the web is in direct contact with the faces of the press rolls. An example of the type of roll used in a smoothing press is a roll whose mantle is formed of cast iron, the outer surface of which is coated with rubber.
In conventional arrangements wherein smoothing presses are utilized, the web is passed unsupported, i.e., as an open draw, from the press section into the smoothing press nip and from there the web is passed as an open draw, unsupported by a fabric, to the drying section. In this connection, the web is most commonly passed from the smoothing press nip onto a so-called baby cylinder or lead-in cylinder of the drying section. Such baby or lead-in cylinders are steam-heated drying cylinders, the effective drying capacity of which is relatively low due to the relatively small cover angle of the web on the baby cylinder. For this reason, these cylinders are generally not included in determining the effective number of drying cylinders in the drying section.
There is a considerable risk web breakage on the open draw of the web between the press section and the baby cylinder of the drying section and, in particular, on the open draw which exists after the smoothing press. Such web breakage often necessitates shutting down the paper machine for relatively long periods of time. The risk of web breakage which is particularly high in the case of thin paper webs is due to the fact that the web is still relatively weak and flexible after the press section so that web fluttering induced by air currents or other circumstances may result after the press section with resulting web breaks.